1. Technical Field
The invention disclosed broadly relates to electrical computers and data processing systems and more particularly relates to data processing systems and methods for editing structured document text.
2. Background Art
Modern word processing and text editing programs employ structured document architecture to provide greater control and flexibility in the displayed and printed appearance of documents prepared with the programs. Structured document architecture is described, for example, in the below referenced U.S. patent application by Bennett, et al. A structured document can be prepared in accordance with the Standardized General Markup Language, such as is described in the International Standards Organization, Standard 8879-1986. A data stream of text marked up in accordance with the Standardized General Markup Language, will have its text divided into elements consisting of a begin tag and its content and terminated by an end tag, when necessary. Within a WYSIWYG (what you see is what you get) editor, text is displayed to the user as it will appear when it is printed, even though its structure is defined by the begin tags and end tags for each element of text. Formatting of the elements within a structured document is done when the document is displayed to the user. Those elements which fall into the category of commonly used elements include paragraphs, simple lists, ordered lists, bulleted lists, list items, headings, and document titles. A hierarchical structure can be attributed to these various elements, such as assigning the title element as having the highest level in a hierarchy, assigning a chapter heading as having a next highest level in the hierarchy, and assigning a paragraph element as having a third highest level in an example structured document hierarchy.
Modern displays and printers are capable of representing strings of text in highlighted conditions, which are generally referred to as "emphasis." Example types of emphasis include bold face, color, italic, monospace font, overstrike, subscript, superscript, underscore, and other defined symbols. In a structured document architecture, the portion of the displayed and printed text which will be emphasized by a particular type of emphasis, will be defined by a begin tag and an end tag which characterizes the type of emphasis.
In a structured document architecture having emphasis display capability, if the text displayed on the display unit during the editing operation is in the WYSIWYG form, existing emphasis begin and end tags which are embedded in the structured document text, will not have their positions precisely shown on the display screen. Thus, during editing operations, when the user wishes to delete existing emphasis characteristics by removing the corresponding emphasis begin and end tags, the user's ability to distinguish the exact location of each respective tag will be impaired by the tags having been concealed in the WYSIWYG display. If the user fails to remove both the begin tag and the end tag corresponding to the emphasis characteristic to be removed, the editing operation will be incomplete. Another problem occurs when the user wishes to have two or more forms of emphasis for the same portion of text. The user must be able to accurately place both the begin tag and the end tag for an added emphasis characteristic at the desired locations in the structured document text. However, since WYSIWYG display conceals the exact location in which the begin tag and end tag need to be placed, an incomplete operation will occur.
An additional consideration must be given to those structured document architectures which prohibit certain types of emphasis occurring for particular types of parent document structures. For example, many structured document architectures will prohibit the use of the overstrike form of emphasis in a title or a chapter heading. Unless the user has a detailed understanding of the structured document architecture, it is likely that mistakes will be made in attempting to add emphasis characteristics to prohibited parent structures in a document.
3. Related Patent Applications
The following patent applications serve to describe the background of the invention and are incorporated herein by reference:
U.S. patent application Ser. No. 344,322, filed Apr. 26, 1989, now abandoned, by Bennett, et al., entitled "A Method for Manipulating Elements Within a Structured Document Using Active Intent Interpretation," assigned to the IBM Corporation, and incorporated herein by reference.
U.S. patent application Ser. No. 344,342, filed Apr. 26, 1989, to Lim, et al., now abandoned, entitled "A Method for Copying a Marked Portion of a Structured Document," assigned to the IBM Corporation and incorporated herein by reference.
U.S. patent application Ser. No. 344,343, filed Apr. 26, 1989, to Lim, et al., now U.S. Pat. No. 5,140,521, entitled "A Method for Deleting a Marked Portion of a Structured Document," assigned to the IBM Corporation and incorporated herein by reference.